#include <bits/stdc++.h>
using namespace std;
 
void pVec(vector<int> f){
	for(auto i : f) cout << i << " ";
	cout << endl;
}
int main() {
	int t,n; cin >> t;
	while(t--){
		cin >> n;
 
		vector<int> a(n),b(n);
		for(int i=0;i<n;i++)	cin >> a[i];
		for(int i=0;i<n;i++)	cin >> b[i];
 
		int mxa = *max_element(a.begin(),a.end()), mxb = *max_element(b.begin(),b.end());
 
		if(mxa >= mxb)	for(int i=0;i<n;i++){	if(a[i] <= b[i]) swap(a[i],b[i]);}
		else	for(int i=0;i<n;i++){	if(a[i] > b[i]) swap(a[i],b[i]);}
 
		mxa = *max_element(a.begin(),a.end()), mxb = *max_element(b.begin(),b.end());
		cout << mxa * mxb << endl;
	}
	return 0;
}

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Mwo2CjEgMiA2IDUgMSAyCjMgNCAzIDIgMiA1CjMKMyAzIDMKMyAzIDMKMgoxIDIKMiAxCg==

3
6
1 2 6 5 1 2
3 4 3 2 2 5
3
3 3 3
3 3 3
2
1 2
2 1